Definitions have been provided to help with a general understanding of network transmissions and are not meant to limit their interpretation or use thereof. Thus, one skilled in the art may substitute other known definitions or equivalents without departing from the scope of the present invention.
Datagram: A portion of a message transmitted over a packet-switching network. One key feature of a packet is that it contains the destination address in addition to the data. In IP networks, packets are often called datagrams.
PUSH: In client/server applications, to send data to a client without the client requesting it. The World Wide Web (WWW) is based on a pull technology where the client browser must request a Web page before it is sent. Broadcast media, on the other hand, utilize push technologies because information is sent out regardless of whether anyone is tuned in.
Increasingly, companies are using the Internet to deliver information push-style. One example of a widely used push technology is e-mail. This is a push technology because you receive mail whether you ask for it or not—that is, the sender pushes the message to the receiver.
PULL: To request data from another program or computer. The opposite of pull is push, where data is sent when a request is being made. The terms push and pull are used frequently to describe data sent over the Internet. As mentioned earlier, the WWW is based on pull technologies, where a page isn't delivered until a browser requests it. Increasingly, however, information services are harnessing the Internet to broadcast information using push technologies. A prime example is the PointCast Network™.
RADIO BROADCASTING: Airborne transmission of audio signals via electromagnetic carrier waves accessible by a wide population by means of standard receivers, such as radios. Radio waves are not only deployed as a carrier in standard radio broadcasting, but also in wireless telegraphy, telephone transmission, television, navigation systems, and radar. Radio waves are of different length and usually identified by their frequency, i.e., the number of times per second that a periodic wave repeats. The shortest waves have the highest frequency, and the longest waves have the lowest frequency. A typical radio communication system features the following two main components: a transmitter and a receiver. The transmitter generates electrical oscillations at a radio frequency called the carrier frequency. In analog radio broadcasting, either the amplitude (AM) or the frequency (FM) itself may be modulated to vary the carrier wave, thereby producing sounds. At the receiver device, the antenna converts the incoming electromagnetic waves into electrical oscillations, which are then increased in intensity by amplifiers. Finally, a speaker in the receiving device converts the electrical impulses into sound waves audible to the human ear. Several types of noise such as static—caused by electrical disturbances in the atmosphere, hum—a steady low-frequency note commonly produced by the frequency of the alternating-current power supply, hiss—a steady high frequency note, or a whistle—a pure high-frequency note produced by unintentional audio-frequency oscillation, cause broadcast interference and distortion at the receiver end.
Currently, approximately 10,000 radio stations are located throughout the U.S.A., reaching a vast audience. U.S. radio stations are operating with analog technology and are almost evenly divided between two broadcast spectrums: amplitude modulation (AM) at 0.525-1.705 MHz and frequency modulation (FM) at 88-108 MHz. A new emerging technology known as in-band on-channel (IBOC) allows these radio stations to deploy digital transmission technology within existing bandwidths allocated to the AM and FM stations. Digital transmission allows data processing in strings of 0's and 1's, rather than analog transmission by means of electronic signals of varying frequency or amplitude that are added to carrier wave of a given frequency. Digital technology is primarily deployed in new communication media, such as computers and fiber-optic networks. By way of example, a modem is used to: modulate outgoing digital signals from a computer to analog signals for a conventional copper twisted pair telephone line, to demodulate the incoming analog signal, and to convert it to a digital signal for the computer in order to facilitate communication via the Internet.
The Internet is an international system of computer networks, comprised of a series of computers interconnected by means of data lines, routers, and/or wireless communication links. Each computer, as a part of the Internet, serves, amongst other things, as a storage device for data flowing between computers. The Internet facilitates data interchange, as well as remote login, electronic mail, and newsgroups. One integral part of the Internet is the World Wide Web (hereafter “the Web” or WWW), a computer-based network of information resources. The Internet is also a transmission medium for e-mails, short messages (SMS) or other data content.
Like traditional computer networks, the Internet operates within the client-server format. Servers are typically remote computer systems that store and transmit electronic documents over the network to other computers upon request. Clients, on the other hand, are computer systems or other interactive devices that request/receive the stored information from a server. A client may be a personal computer or a wireless device such as a handheld, a cellular phone or other Internet-enabled mobile device that is capable of two-way communication.
In the traditional client-server model, a client requests a service or data from a server, which then responds by transmitting the data to the client. As mentioned earlier, this is known as “pull” technology because the client “pulls” data from the server. The Web is a typical example of Pull technology wherein a user sends a data request by entering a Uniform Resource Locator (URL) to a server which then answers by sending the Web site at the requested URL back to the user. In contrast, “push” technology, which also operates within the client-server model, does not require a user initiated data request prior to the transmission of data. Such data transmissions are common in the so-called Web Casting technology, i.e., the prearranged updating of news, weather, or other selected information on the interface of a device with digital capabilities through periodic and generally unobtrusive transmission. Currently, Web Casting technology primarily targets computer users. Yet, as described above, there is a huge audience in the radio broadcast area, and there exists a strong demand for data casting content such as: song titles, artist names, lyrics, traffic and weather news, stock market quotes, pager messages or complementary product information. New radio receivers with Liquid Crystal Displays (LCD) combined with the deployment of the inbound on-channel (IBOC) technology facilitate such data casting.
As known in the art, network communication is based on the seven layer model Open System Interconnection (OSI). Information being transferred from a software application in one communication system to another, e.g., from one computer to another via the Internet, must pass through each of the OSI layers. Each layer has a different task in the information exchange process and the actual information exchange occurs between peer OSI layers. Each layer in the source system adds control information to the transmission data and each layer in the destination system analyzes and removes the control information from that data. At the lowest layer, the physical layer, the entire information packet is placed onto the network medium where it is picked up by the receiving unit. In this model, protocols represent and describe the formal rules and conventions that govern the exchange of information over a network medium. The protocol likewise implements the functions of one or more of the OSI layers. For example, the transport protocol for Web sites is the Hyper Text Transfer Protocol (HTTP), for e-mails Simple Mail Transfer Protocol (SMTP) and for software programs File Transfer Protocol (FTP). Premised in the functions of the used network layers to be implemented and the tasks to be achieved during the communication, protocols vary in their specifications. Many additional protocols exist to assist in standardizing communication standards.
Web sites are formatted in Hyper Text Markup Language (HTML), Wireless Markup Language (WML), or Extensible Markup Language (XML). These are standard text formatting languages for interconnected networks such as the Internet. So-called Web browsing software interprets HTML, WML, and/or XML documents, thereby allowing users to view Web sites on their display screen. As in the case with protocols, additional languages exist for the marking-up of Web sites or other data.
The data link between the Internet and a wireless device is established via a wireless modem or an antenna and a wireless carrier service using radio frequencies, rather than via twisted-pair or fiber-optic cables. Content for wireless services is marked up in Wireless Application Protocol (WAP), rather than HTTP. For that reason, Internet servers cannot directly communicate with, and content cannot be directly sent to wireless devices.
Multimedia content for wireless services place a unique burden on the specific communications system from which it is transmitted. Specific bandwidth requirements for multimedia far exceed those required by typical prior art audio only broadcast radio. In addition, the inclusion of high bandwidth data in a normal broadcast stream significantly slows the data flow to the end user. The prior art has failed to implement a broadcast system that efficiently and effectively transmits data content to include large bandwidth data through a radio broadcast system.
Prior art solutions to overcoming some of the problems associated with transmitting high bandwidth multimedia content through traditional systems are described briefly below.
U.S. Pat. No. 5,878,223 (Becker et al.) provides for a “System And Method For Predictive Caching Of Information Pages.” A computer, e.g. a server or computer operated by a network provider sends one or more requesting computers (clients) a most likely predicted-to-be selected (predicted) page of information by determining a preference factor for this page based on one or more pages that are requested by the client. This page is added to a local cache of predicted-to-be-selected pages in the client.
U.S. Pat. No. 5,732,267 (Smith) provides for “Caching/Prewarming Data Loaded From CD-ROM.” Data defining pages and objects of a multimedia work are transferred in the background to minimize delays that would otherwise be incurred. In playing a multimedia work that is recorded on a CD-ROM, a personal computer (10) that includes a central processing unit (CPU) (23) transfers data for selected pages and for objects on a page of the multimedia work into a cache, using free CPU cycles, so that the data are available when needed. This technique is particularly useful in transferring data for animation objects of a multimedia work, since it enables two animations to play concurrently without incurring a delay to load the data for the second animation when the page is loaded and avoids interrupting the execution of the first animation at the time that the second animation must start executing.
U.S. Pat. No. 6,055,569 (O'Brien, et al.) provides for “Accelerating Web Access By Predicting User Action.” A smart browser works in conjunction with an HTTP server selectively downloading WWW pages into the browser's memory cache. The determination of which pages to download is a function of a probability weight assigned to each link on a Web page. By evaluating that weight to a predetermined browser criteria, only those pages most probably to be downloaded are stored in the browser's memory cache. The download is done in the background while the browser user is viewing the current Web page on the monitor. This greatly enhances the speed with which the viewer can “cruise” the Web while at the same time conserving system resources by not requiring the system to download all the possible links.
U.S. Pat. No. 5,802,292 (Mogul) provides for a “Method For Predictive Prefetching Of Information Over A Communications Network.” A method for predictive prefetching of objects over a computer network includes the steps of providing a client computer system, providing a server computer system, the server computer system having a memory, a network link to the client computer system, the network link also providing connection of the server computer system to the computer network, requesting from the server computer system by the client computer system a retrieval of a plurality of objects, retrieving the plurality of objects by the server system, storing the retrieval and an identity of the client computer system in the memory of the server computer system, sending the plurality of objects from the server computer system to the client computer system over the network link, predicting in the server computer system a plurality of subsequent retrieval requests from the client computer system according to a predetermined criteria, sending the prediction to the client computer system, and prefetching by the client computer system an object based on the prediction and other information. With such an arrangement, an object may be prefetched before a user actually requests it. This makes the retrieval latency appear to be zero when a user requests a prefetched object.
U.S. Pat. No. 5,682,441 (Ligtenberg, et al.) provides for a “Method And Format For Storing And Selectively Retrieving Image Data.” A method of processing an input image for storage includes decomposing the input image into a number of images at various resolutions, subdividing at least some of these images into tiles (rectangular arrays) and storing a block (referred to as the “tile block”) representing each of the tiles, along with an index that specifies the respective locations of the tile blocks. In specific embodiments, the tiles are 64.times.64 pixels or 128.times.128 pixels. The representations of the tiles are typically compressed versions of the tiles. In a specific embodiment, JPEG compression is used. In a specific embodiment, an operand image is recursively decomposed to produce a reduced image and a set of additional (or complementary) pixel data. At the first stage, the operand image is normally the input image, and for each subsequent stage, the operand image is the reduced image from the previous stage. At each stage, the reduced image is at a characteristic resolution that is lower than the resolution of the operand image. The processing is typically carried out until the resulting reduced image is of a desired small size.